DNA of the alleged killer of Officer Russel Timoshenko was found on the gun used against the rookie cop, a forensics expert testified yesterday.

Criminalist Rebecca Mikulasovich said swabs taken from the silver .45-caliber handgun provided a match for the DNA of suspected triggerman Dexter Bostic.

DNA matching that of another defendant, Lee Woods, 30, was found on the other two guns cops recovered near the BMW in which the suspects were riding on July 9, 2007, when they allegedly fired on Timoshenko and partner Herman Yan.

One of those guns, a 9mm Hi-Point, was the weapon that wounded Yan. The third gun, an Intertech 9mm, was not fired during the attack.

The DNA of the third defendant, Robert Ellis, 36, who prosecutors say fired the Hi-Point at Yan, was not found any guns.

Bostic’s lawyer, Edward Wilford, said the evidence suggested only that his client handled the gun.

Jurors, who were kept past 9:30 p.m. last night, also saw a 3-D computer animation, the first of its kind presented in court by the NYPD Crime Scene Unit, showing the positions of the vehicles and the trajectories of the bullets.